The NYPD is searching for a reputed Brooklyn gang-banger who threatened cops by posting an online photo of a man opening fire into a marked police cruiser — just hours after two cops were assassinated the same way, law-enforcement sources told The Post on Sunday.

Devon Coley, 18, wrote the chilling phrase “73Nextt”– an apparent reference to the 73rd Precinct in the Oceanville-Brownsville section where he lives — on his Facebook page.

A “wanted” poster issued by the NYPD that identifies Coley as a member of the “ATC/180HII Crew” says the alarming picture “seems to be taken from a movie.”

“We are taking it seriously,” a law-enforcement source said, adding that charges against Coley were being mulled.

The threat is among several that have been made against the NYPD since cops Wenjian Liu and Rafael Ramos were gunned down execution-style as they sat in a marked police cruiser in Brooklyn on Saturday afternoon.

Around noon Sunday, an anonymous caller phoned Staten Island’s 120th Precinct and vowed: “I’m going to shoot a cop in the head today and it will be on Staten Island,” sources said.

In Memphis, the Department of Homeland Security and local cops interviewed a young man who wrote online that he was heading to New York to kill two more cops but didn’t file any charges after he said he was drunk when he did it, sources said.

The Tennessee man, Daryl Lofton, 26, was the subject of an all-points bulletin after allegedly writing “Good Job #F–k12 Kill em all i’m on the way to NY now #shootthepolice 2 more going down tomorrow.”

Lofton’s Instagram account, under the name “woodgramflexinn,” has since been suspended.